1 files changed, 91 insertions, 0 deletions
diff --git a/src/fortran/lapack/zrot.f b/src/fortran/lapack/zrot.f
new file mode 100644
index 0000000..9c548e2
--- /dev/null
+++ b/src/fortran/lapack/zrot.f
@@ -0,0 +1,91 @@
+      SUBROUTINE ZROT( N, CX, INCX, CY, INCY, C, S )
+*
+*  -- LAPACK auxiliary routine (version 3.1) --
+*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
+*     November 2006
+*
+*     .. Scalar Arguments ..
+      INTEGER            INCX, INCY, N
+      DOUBLE PRECISION   C
+      COMPLEX*16         S
+*     ..
+*     .. Array Arguments ..
+      COMPLEX*16         CX( * ), CY( * )
+*     ..
+*
+*  Purpose
+*  =======
+*
+*  ZROT   applies a plane rotation, where the cos (C) is real and the
+*  sin (S) is complex, and the vectors CX and CY are complex.
+*
+*  Arguments
+*  =========
+*
+*  N       (input) INTEGER
+*          The number of elements in the vectors CX and CY.
+*
+*  CX      (input/output) COMPLEX*16 array, dimension (N)
+*          On input, the vector X.
+*          On output, CX is overwritten with C*X + S*Y.
+*
+*  INCX    (input) INTEGER
+*          The increment between successive values of CY.  INCX <> 0.
+*
+*  CY      (input/output) COMPLEX*16 array, dimension (N)
+*          On input, the vector Y.
+*          On output, CY is overwritten with -CONJG(S)*X + C*Y.
+*
+*  INCY    (input) INTEGER
+*          The increment between successive values of CY.  INCX <> 0.
+*
+*  C       (input) DOUBLE PRECISION
+*  S       (input) COMPLEX*16
+*          C and S define a rotation
+*             [  C          S  ]
+*             [ -conjg(S)   C  ]
+*          where C*C + S*CONJG(S) = 1.0.
+*
+* =====================================================================
+*
+*     .. Local Scalars ..
+      INTEGER            I, IX, IY
+      COMPLEX*16         STEMP
+*     ..
+*     .. Intrinsic Functions ..
+      INTRINSIC          DCONJG
+*     ..
+*     .. Executable Statements ..
+*
+      IF( N.LE.0 )
+     $   RETURN
+      IF( INCX.EQ.1 .AND. INCY.EQ.1 )
+     $   GO TO 20
+*
+*     Code for unequal increments or equal increments not equal to 1
+*
+      IX = 1
+      IY = 1
+      IF( INCX.LT.0 )
+     $   IX = ( -N+1 )*INCX + 1
+      IF( INCY.LT.0 )
+     $   IY = ( -N+1 )*INCY + 1
+      DO 10 I = 1, N
+         STEMP = C*CX( IX ) + S*CY( IY )
+         CY( IY ) = C*CY( IY ) - DCONJG( S )*CX( IX )
+         CX( IX ) = STEMP
+         IX = IX + INCX
+         IY = IY + INCY
+   10 CONTINUE
+      RETURN
+*
+*     Code for both increments equal to 1
+*
+   20 CONTINUE
+      DO 30 I = 1, N
+         STEMP = C*CX( I ) + S*CY( I )
+         CY( I ) = C*CY( I ) - DCONJG( S )*CX( I )
+         CX( I ) = STEMP
+   30 CONTINUE
+      RETURN
+      END